How long can a huge fortune without an owner quietly gather interest before someone gets the bright idea of taxing it at 99%? Or before it gets lost, converted into occupation currency, nationalized, redesignated or otherwise plundered? If I wanted to preserve wealth like that I'd put it in dozens of accounts all over the world, as private as possible. I'd seek out countries and families with long histories of good banking practice and take my business there. And if I were really wealthy I'd have part of the interest pay for a permanent staff of lawyers devoted to continually improving the defenses.
Put it in diamonds or something like that.
This is the ne plus ultra of arrogant self absorbtion.